a nursery triptych - sprayers...
TRANSCRIPT
A Nursery Triptych Three studies in spraying
Dr. Jason Deveau ● OMAFRA Application Technology Specialist ● Winter 2015
The Garden of Earthly Delights - Hieronymus Bosch, c. 1500
Backpack vs.
Mistblower
Horticultural Crops Ontario, the grower co-operators, Vaughn Agricultural Research Services Inc., Ms. Kathryn Hoshkiw and Ms. Carly Decker are
gratefully acknowledged for making this research possible.
• Is there a significant difference in how spray is deposited when the same volume-per-hectare is applied using an air blast sprayer versus a hand boom versus a mist blower?
The question
• Air blast applications were compared to hand boom in mature highbush blueberry, apple and grape plants using water-sensitive paper (2012)
• Air blast applications were compared to mist blower in peach, raspberry and grape plants using water-sensitive paper (2013)
• If drift isn’t a concern, the mist blower resulted in the most consistent coverage, with a higher droplet density and par surface coverage compared to air blast
• Handboom coverage was typically poor
Typical Airblast Coverage
Typical Mist Blower Coverage
Thanks to Kristy Grigg-McGuffin (OMAFRA Pome Fruit IPM Specialist), summer students Taylor Wallace, Carly Decker, Megan Leedham, and Tara
Wiedeman, statistical expertise by Behrouz Ehsani, and the grower co-operators for making this research possible.
Crop-Adapted
Spraying
• Most pesticide label rates reflect the area of the planting (e.g. L/ha), not the area-density of the plant canopy
• A fixed, prescribed spray volume and/or rate is insufficient to match plant canopy variability
• An hectare of corn is a hectare of corn, but a hectare of whips or shrubs…
• An hectare of corn is a hectare of corn, but a hectare of whips or shrubs…
Possible impacts
Over Spraying Under Spraying
> Money in chemicals/time < Efficacy
> Unnecessary contamination > Pest resistance over time
> Spraying to compensate
• The CAS model adjusts the amount of pesticide per unit ground area to achieve consistent foliar coverage for canopies of varying shape and density
• When achieved with sufficient accuracy, pesticide efficacy is maintained
How does it work?
The method
• In Ontario, I’m testing this in apple orchards, but Dr. Heping Zhu is doing it in nurseries using his Intelligent Sprayer
• First, the operator has to calibrate the sprayer – preferably for each significantly different crop…
The goal is to achieve a minimum of
85 medium sized droplets per cm2 and a total area of 10-15% coverage for most foliar
insecticides / fungicides
2011 - Preliminary Trials
• Based on CAS, an Ontario apple orchard applied ~35% less Mancozeb© than label rate for one season (no control)
Saved $4,140.00 that year just for
one fungicide
Surplus Pesticide
Harvest Quality Harvest Quality
2011 - Powdery mildew in roses
• Similarly, in 2011 we controlled PM in roses using optimized rates
2012 – RIP Ontario apple blossoms
© G
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Gao
– O
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Sta
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2013 and 2014 - Full Trials
• Sprayer operators used the optimized settings and rates for the CAS (treatment) block, and their typical methods for the control blocks
• Students scouted each week for 13-15 weeks and apples were collected at harvest
Orchard saved 39% compared to control blocks
• Sometimes pest / damage counts were significantly higher for CAS and sometimes for control
• However, when the actual counts over the season were graphed, they never came anywhere near spray or economic threshold
Results
Two Spotted Spider Mite (2013)
• Leaves sampled and nymphs and adults counted under microscope
Two Spotted Spider Mite (2014)
• Leaves sampled and nymphs and adults counted under microscope
• CAS worked in both high density and semi-dwarf orchards – Heping showed this method can work in nurseries
Conclusions
• Orchardists reported that these methods were intuitive and that they would be willing to expand their use of use CAS
• Use water-sensitive paper and calibrate based on coverage
Horticultural Crops Ontario, Ground Covers Unlimited, Pentair (Hypro) and Nemapro are gratefully acknowledged for making this research possible
Nematode
Re-suspension
• Responded to grower claim that nematode applications were becoming less effective
• Determined that the concentration of nematodes was dropping significantly over the course of the spray application
The problem
Grower identity cleverly protected Grower identity cleverly protected
Pump
Strainer
Pressure
Gauge
Tank
Bypass
Boom and
Nozzle(s)
Agitator
Tip Strainers
• There’s only so many places they could be going…
• Maybe they’re stranded on the poly tank walls like soap scum… If so, can we rinse them off?
• Collected samples over the course of spraying and counted nematodes per ml
@ spray_guy Jason Deveau
THANK YOU QUESTIONS?